Wish.com app has a lot of...'alternative' versions of these for around £30-40. Wasn't sure about the quality, and haven't been able to compare to a genuine one, but I've been happy with mine so far. Seems well made, strong, the straps are solid. The only thing is, I'm not sure if it's waterproof at all because it came with a waterproof cover to go over the top and because I carry my laptop in it, there's no way I'm chancing it to find out. Mine is OK in light showers, caught out in a heavy downpour once on the M6, contents stayed dry although I'd prefer to use a cover if regularly exposed to heavy rain, I don't think many back packs are 100% waterproof 100% of the time